58 HEROES OF INVENTION AND DISCO VER Y. 



of Davy's father's house, that they would thus stand successively, 

 and in this order, at the head of the most distinguished scientific 

 association in England. 



It is impossible for us in this place to attempt anything more 

 than the most general sketch of Sir Humphrey Davy's numerous 

 and most important discoveries in chemical science. Even his 

 earliest publication, the title of which we have already tran- 

 scribed, was regarded as, for the first time, introducing light 

 and order into an interesting department of the science, — the 

 theory of the various combinations of oxygen and nitrogen, the 

 two gases which, mixed together in certain proportions, form 

 our common atmospheric air, but in other proportions produce 

 compounds of an altogether dissimilar character. The first 

 memoir by Davy which was read before the Royal Society was 

 presented by him in 1801, before he was a member. It an- 

 nounced a new theory, which is now generally received, of the 

 galvanic influence, or the extraordinary effect produced by two 

 metals in contact with each other, when applied to the muscle 

 even of a dead animal, which the Italian professor, Galvani, had 

 some years before accidentally discovered. It was supposed, both 

 by Galvani and his countryman Volta, who also distinguished 

 himself in the investigation of this curious subject, that the 

 effect in question was an electrical phenomenon — whence 

 galvanism used to be called animal electricity ; but Davy 

 showed, by many ingenious experiments, that, in order to pro- 

 duce it, the metals in fact underwent certain chemical changes. 

 Indeed, he proved that the effect followed when only one metal 

 was employed, provided the requisite chemical change was by 

 any means brought about on it — as, for example, by the inter- 

 position between two plates of it, of a fluid calculated to act 

 upon its surface in a certain manner. In his Bakerian LectJire 



